Check the following to resolve the issue:
- Make sure to install the latest software update on the TV.
- The USB cable should be connected securely to your TV and mobile device.
- Check whether the USB cable supports data transfers. Don't use USB cables that are only exclusive for charging.
- If the mobile device uses Media Transfer Protocol (MTP), change the settings on your mobile device to Mass Storage Class (MSC).
- You can use the Picture Transfer Protocol (PTP) depending on the TV model.
- For the specifications and setting methods of your mobile device, refer to the supplied manual.
To operate the MSC connection setting on an Xperia™ Z3:
- From the Home screen, select Settings.
- Select Xperia Connectivity.
- From the USB Connectivity category select the USB connection mode.
- Select Mass storage mode (MSC).
If it still doesn't recognize the mobile device, it's possible that the internal memory doesn't support MSC. Transfer the data (pictures, etc.) to an SD card or other type of removable memory.